<?php
abstract class Capacity extends Coffee {
    protected $coffee;
    public function __construct(Coffee $coffee)
    {
        $this->coffee = $coffee;
    }

    public function getDescription()
    {
        return $this->coffee->getDescription() . $this->description;
    }

    public function cost()
    {
        return $this->pay + $this->coffee->cost();
    }
}